feat: add preset in server

api/models/schema/presetSchema.js

@@ -0,0 +1,27 @@
+const mongoose = require('mongoose');
+const conversationPreset = require('./conversationPreset');
+const presetSchema = mongoose.Schema(
+  {
+    presetId: {
+      type: String,
+      unique: true,
+      required: true,
+      index: true
+    },
+    title: {
+      type: String,
+      default: 'New Chat',
+      meiliIndex: true
+    },
+    user: {
+      type: String,
+      default: null
+    },
+    ...conversationPreset
+  },
+  { timestamps: true }
+);
+
+const Preset = mongoose.models.Preset || mongoose.model('Preset', presetSchema);
+
+module.exports = Preset;